Measurement of 125I by liquid scintillation methods

The decay scheme of 125I is examined for the explanation of the observed pulse height spectrum and counting efficiency measured by liquid scintillation methods. The pathways of energy release in the form of kinetic energy of electrons (conversion of Auger electrons) is explained. Two major energy groups are predicted at 12 and 40 keV. These two groups were observed in the liquid scintillation systems. The measured counting efficiency in an unquenched emulsifier scintillator solution and a coincidence type liquid counter was 76%. The effects of quenching on the counting efficiency and pulse height spectrum of 125I were measured. (Auth.)